Spatial Navigation

In these projects and collaborations, the goal is to find neural and behavioral markers of spatial (dis-)orientation. All projects leverage synchronized motion and EEG recordings. Using VR hardware, novel paradigms probe human navigators to make efficient decisions about spatial goals. Modeling the navigators brain and movement patterns, I strive to predict future success overcoming spatial challenges. Critically, spatial orientation skills worsen with the progression of several neurodegenerative diseases such as Alzheimer’s. Patients often attribute challenges maintaining their sense of direction as a core limitation in their day to day lives. This research can help design adaptive systems, that ease key symptoms. Finding the right level of automation to keep the human engaged in the spatial task is a noteworthy implication.

6. Single‐trial Regression of Spatial Exploration Behavior Indicates Posterior EEG Alpha Modulation to Reflect Egocentric Coding
Lukas Gehrke, Klaus Gramann | Eur J Neurosci. 2020; 00: 1– 10.

We showcase the capabilities of Mobile Brain/Body Imaging (MoBI) using Virtual Reality (VR), demonstrating several analyses approaches based on general linear models (GLM) to reveal behavior‐dependent brain dynamics. Confirming spatial learning via drawn sketch maps we employed motion capture to image spatial exploration behavior describing a shift from initial exploration to subsequent exploitation of the mental representation. 

📄Paper | 👨🏽‍💻Project on Researchgate

5. The Audiomaze: An EEG and motion capture study of human spatial navigation in sparse augmented reality
Makoto Miyakoshi, Lukas Gehrke, Klaus Gramann, Scott Makeig, John R. Iversen | Eur J Neurosci. 2020; 00: 1– 10.

We developed the Audiomaze, a novel paradigm in which participants freely explore a room-sized virtual maze while EEG is recorded synchronized to motion capture. Participants (n=16) were blindfolded and explored different mazes, each in three successive trials, using their right hand as a probe to ‘feel’ for virtual maze walls. We found behavioral evidence of navigational learning in a sparse-AR environment, and a neural correlate of navigational learning was found near lingual gyrus.

📄Paper | 👨🏽‍💻Project on Researchgate

4. Mobile brain/body imaging of landmark-based navigation with high-density EEG
Alexandre Delaux, Jean-Baptiste de Saint Aubert, Stephen Ramanoël, Marcia Bécu, Lukas Gehrke, Marius Klug, Ricardo Chavarriaga, José-Alain Sahel, Klaus Gramann, Angelo Arleo | bioRxiv 2021.01.13.426330; doi: https://doi.org/10.1101/2021.01.13.426330

In this work, we focused on landmark-based navigation in actively behaving young adults solving a virtual reality Y-maze task. Our results confirm that combining mobile high-density EEG and biometric measures can help unravel the brain network and neural modulations subtending ecological landmark-based navigation.

📄Preprint | 👨🏽‍💻Project on Researchgate

IMT Task

3. The Invisible Maze Task (IMT): Interactive Exploration of Sparse Virtual Environments to Investigate Action-Driven Formation of Spatial Representations.
Lukas Gehrke, John R. Iversen, Scott Makeig and Klaus Gramann | In: Creem-Regehr S., Schöning J., Klippel A. (eds) Spatial Cognition XI. Spatial Cognition 2018. Lecture Notes in Computer Science, vol 11034. Springer, Cham

The neuroscientific study of human navigation has been limited by requiring participants to remain stationary during data recordings. With the Invisible Maze Task (IMT) we provide a novel VR paradigm to investigate freely moving, naturally interacting, navigators.

📄Paper | 📽Slides | 💾VR Simulation | 👨🏽‍💻Project on Researchgate

2. Mobile Brain/Body Imaging (MoBI) of Spatial Knowledge Acquisition during Unconstrained Exploration in VR.
Lukas Gehrke and Klaus Gramann | In Proceedings of the First Biannual Neuroadaptive Technology Conference (pp. 22–23). Berlin, Germany. 

Using the Invisible Maze Task (IMT) we show that study participants navigate with increasing efficiency as they learn the layout of a maze.

📝Talk Abstract

1. Heading computation in the human retrosplenial complex during full-body rotation.
Klaus Gramann, Friederike U. Hohlefeld, Lukas Gehrke and Marius Klug | bioRxiv (2018). https://doi.org/10.1101/417972

We contrasted physically rotating participants with a traditional joystick setup with rotations based on visual flow only. We show that varying rotation velocities were accompanied by pronounced beta synchronization during physical rotation but not joystick control.

📄Preprint

in the media

German newspaper Der Spiegel featured the invisible maze task in Seidler’s Selbstversuch series.

https://www.moz.de/nachrichten/brandenburg/artikel-ansicht/dg/0/1/1668674/

The invisible maze task was featured on RBB Television starring DAAD RISE guest Luke Guerdan.

Together with 6sept13, I produced an image film about the Berlin Mobile Brain/Body Imaging Lab.

Applications in Human-Computer Interaction (HCI)

In extended realities (VR/AR/MR) sampling body movements enables the design of natural interactions. In concert with neural markers, detecting where things start to feel off as well as building novel interactions is feasible. My core motivation is bringing neuroscientific research findings to application, leveraging a variety of supplementary signals, such as body movements and other wearables, to design robust interactive experiences that feel natural.

2. Detecting Visuo-Haptic Mismatches in Virtual Reality using the Prediction Error Negativity of Event-Related Brain Potentials.
Lukas Gehrke, Sezen Akman, Pedro Lopes, Albert Chen, Avinash Kumar Singh, Hsiang-Ting Chen, Chin-Teng Lin and Klaus Gramann | In Proceedings of the 2019 CHI Conference on Human Factors in Computing Systems (CHI ’19). ACM, New York, NY, USA, Paper 427, 11 pages. DOI: https://doi.org/10.1145/3290605.3300657

We detected conflicts in visuo-haptic integration by analyzing event-related potentials (ERP) during interaction with virtual objects. In our EEG study, participants touched virtual objects and received either no haptic feedback, vibration, or vibration and EMS (Electrical muscle stimulation). We report a sensitiviy to unrealistic VR situations of an early negativity component at electrode FCz (prediction error), indicating we successfully detected haptic conflicts.

📄Paper | 📽Slides | 💾Data/Code

Together with Sezen Akman who wrote her excellent Masterthesis within the project we won Best Project Award at “VDI Mensch und Technik 2019” endowed with 3000€.

🧾Poster

1. Neurofeedback during Creative Expression as a Therapeutic Tool
Stephanie Scott and Lukas Gehrke | Springer Series on Bio- and Neurosystems, Vol. 10, Jose L. Contreras-Vidal et al. (Eds): Mobile Brain-Body Imaging and the Neuroscience of Art, Innovation and Creativity, 978-3-030-24325-8

Using EEG power we gave a live visual feedback of white lines on a black background, borrowing from Joy Division’s famous album cover. This closed-loop neurofeedback stimulates creativity by making aware one’s own brain activity.

📄Paper | PDF

in the media

(credit to collaborator Pedro Lopes at @UChicago):
https://news.uchicago.edu/story/how-make-electrical-muscle-stimulation-feel-natural-virtual-reality-users

https://www.vdi.de/news/detail/vdi-ehrt-die-besten

https://www.vdi.de/news/detail/vdi-ehrt-die-besten

Methods for an Integrated Analyses of Movement and Physiology

In several projects we pushed the investigation of human brain dynamics with the aid of information derived from full-body movement and studies with an interest in motor behavior using brain imaging as an additional source of information.

4. MoBI – Mobile Brain/Body Imaging
Evelyn Jungnickel, Lukas Gehrke, Marius Klug and Klaus Gramann | Academic Press, Neuroergonomics, 59—63, 2019 

Mobile brain/body imaging (MoBI) is a method to record and analyze brain dynamics and motor behavior in naturalistic conditions. In this chapter we give an overview of its suitability to investigate a wide range of scientific problems., including analyses of human brain dynamics with the aid of information derived from movement and studies with an interest in motor behavior using brain imaging as an additional source of information.

📕Book Chapter | 👨🏽‍💻Project on Researchgate

3. Extracting Motion-Related Subspaces from EEG in Mobile Brain/Body Imaging Studies using Source Power Comodulation.
Lukas Gehrke*, Luke Guerdan* and Klaus Gramann | 9th International IEEE/EMBS Conference on Neural Engineering (NER), San Francisco, CA, USA, 2019, pp. 344-347 | * contributed equally

We propose the use of a supervised spatial filtering method, Source Power Co-modulation (SPoC), for extracting source components that co-modulate with body motion. We illustrate the approach to investigate the link between hand and head movement kinematics and power dynamics of EEG sources while participants explore an invisible maze in virtual reality.

📄Paper

2. The BeMoBIL Pipeline – Facilitating Mobile Brain/Body Imaging (MoBI) Data Analysis in MATLAB
Marius Klug, Lukas Gehrke, Friederike U. Hohlfeld and Klaus Gramann | In Proceedings of the 3rd International Conference on Mobile Brain/Body Imaging, 2018, https://doi.org/10.14279/depositonce-7236

A collection of Matlab scripts and functions for an integrated and streamlined analyses of EEG and movement data.

🧾Poster | 💾BeMoBIL Pipeline Code

1. Prototypical Design of a Solution to Combine Head- Mounted Virtual Reality and Electroencephalography.
Richard Wenzel, Lukas Gehrke and Klaus Gramann | In Proceedings of the 3rd International Conference on Mobile Brain/Body Imaging, 2018, https://doi.org/10.14279/depositonce-7236

We developed and tested a prototype of printable spacers to improve signal quality by preventing electrode movement when combining high-density active electrode EEG headsets with modern VR headsets.

🧾Poster | 💾3D CAD model